Tissue resident macrophages are increasingly recognized as important determinants of organ homeostasis, tissue repair, remodeling, and regeneration. While the ontogeny and function of tissue resident macrophages has been identified as distinct from postnatal hematopoiesis, the inability to specify, in vitro, similar populations that recapitulate these developmental waves has limited our ability to study their function and potential for regenerative applications.
We took advantage of the concept that tissue resident macrophages and monocyte-derived macrophages originate from distinct extraembryonic and definitive hematopoietic lineages to devise a system to generate pure cultures of macrophages that resemble tissue resident or monocyte-derived subsets. We demonstrate that hPSC-derived extra-embryonic-like and intra-embryonic-like hematopoietic progenitors differentiate into morphologically, transcriptionally, and functionally distinct macrophage populations. Single cell RNA sequencing of developing and mature cultures uncovered distinct developmental trajectories and gene expression programs of macrophages derived from extra-embryonic-like and intra-embryonic-like hematopoietic progenitors. These findings establish a resource to generate human tissue resident-like macrophages to study their specification and function under defined conditions and to explore their potential use in tissue engineering and regenerative medicine applications.
